Soft or plasticized polyvinyl chloride compositions are used for many purposes in industry. However, the plasticization of the PVC results in a clear deterioration of the flame resistance of the polyvinyl chloride. For this reason it has been tried repeatedly to make polyvinyl chloride compositions more fire resistant, particularly less inflammable, by either adding flame-retarding plasticizers or by the incorporation of additional flame-retarding substances (see, for example, Published German applications Nos. DOS 19 26 412, 19 31 697; and 24 59 957). Such plasticizers and additives, however, caused in the past, a deterioration of the mechanical, chemical and/or electrical properties of these plasticized polyvinyl chloride compositions, and the flame resistance was not always satisfactory.